OZ-13MSX2 Mercurius

The OZ-13MSX2 Mercurius was a prototype defensive anti-Gundam mobile suit developed by the five captured Gundam Scientists for OZ in After Colony 195. Designed to operate alongside its sibling unit, the offensive OZ-13MSX1 Vayeate, the Mercurius specialized in defence through its signature armament of ten planet defensors—small disc-shaped objects that generated electromagnetic fields capable of repelling attacks from even the XXXG-00W0 Wing Gundam Zero’s twin buster rifles. The Mercurius was primarily piloted by Heero Yuy and later by Quatre Raberba Winner whilst they were under OZ custody.

Overview

The Mercurius and Vayeate were developed using the OZ-12SMS Taurus as a reference, representing OZ’s attempt to create mobile suits capable of defeating the Gundams. The five captured Gundam Scientists designed the pair as complementary units—Mercurius providing virtually impenetrable defence whilst Vayeate delivered overwhelming firepower.

The Mercurius was designed with defensive strategy in mind. Its ten planet defensors could generate electromagnetic barriers that repelled just about any attack, protecting not only the Mercurius itself but also allied mobile suits. The planet defensors could be weakened by sustained powerful attacks, at which point they returned to the Mercurius for recharging, making the mobile suit’s defensive capability renewable rather than consumable.

For offence, the Mercurius carried a small beam gun ideal for close combat and a large “crash shield” with an integrated beam saber. This weapon allowed the Mercurius to block and attack almost simultaneously, making it dangerous in close quarters despite its defensive specialization. Like the Vayeate, the Mercurius mounted a cover to protect its head sensor, though this limited vision—a necessary trade-off for enhanced sensor protection.

The Mercurius’ planet defensor technology proved so effective that it was later incorporated into OZ’s mass-production mobile dolls, the OZ-02MD Virgo and WF-02MD Virgo II, making the Mercurius’ defensive innovations a cornerstone of subsequent mobile doll development.

Armament

Planet Defensors

The Mercurius was equipped with ten planet defensors mounted on its back—small disc-shaped objects that generated electromagnetic fields for defensive purposes. These could defend the Mercurius itself or allied mobile suits from virtually any attack, including shots from the Wing Gundam Zero’s twin buster rifles.

However, sustained powerful attacks against the planet defensors could weaken them and cause them to lose their ability to produce electromagnetic fields. When low on energy, they could return to the Mercurius for recharging, making the defensive system renewable. This recharging capability gave the Mercurius sustained defensive capability that outlasted weapons with limited ammunition or energy.

Beam Gun

A short-to-middle-range beam firearm. It possessed less power than standard beam rifles, but because of its small size, it was ideal for the close combat role of the Mercurius. The compact weapon allowed the Mercurius to engage enemies whilst maintaining defensive coverage with the crash shield.

Crash Shield

A large shield integrated with a powerful beam saber. This weapon allowed the Mercurius to block and attack almost simultaneously, making it exceptionally dangerous in close combat despite its defensive specialization. The beam saber could cut through titanium alloy and even Gundanium alloy, giving the Mercurius offensive capability when enemies closed to melee range.

Operational history

Development and deployment

Whilst the five Gundam pilots fought on Earth to defeat OZ and the Alliance, the scientists who created their mobile suits were captured by OZ and forced to work on next-generation mobile suits to end the Gundam pilots’ activities. The five scientists developed a pair of designs—the defensive OZ-13MSX2 Mercurius and the offensive OZ-13MSX1 Vayeate.

The Mercurius was piloted by captured Gundam pilot Heero Yuy, whose combat data was recorded for use in the Virgo’s AI control system. This forced piloting served dual purposes—testing the mobile suits’ capabilities against Gundams whilst gathering data to improve mobile doll programming.

Battle with Wing Gundam Zero

When Quatre Raberba Winner went on a rampage with the newly built Wing Gundam Zero, driven emotionally unstable by the ZERO System, Heero was dispatched with OZ infiltrator and Vayeate pilot Trowa Barton to capture or destroy the renegade Gundam. Heero and Trowa fought Quatre to a standstill using the Mercurius and Vayeate’s complementary capabilities—the Mercurius’ planet defensors blocking the Wing Zero’s devastating twin buster rifle whilst the Vayeate returned fire.

Quatre surrendered after he thought he had killed Trowa (who had intercepted a blast to protect Heero). After the battle, the Wing Gundam Zero, the damaged Mercurius, and the wreckage of the Vayeate were recovered by OZ.

Destruction and mobile doll successor

The damaged Mercurius was eventually set to self-destruct by Quatre in an attempt to destroy the captured Wing Zero as he escaped with Heero. The mobile suit’s destruction eliminated the original, but its technology lived on.

A second Mercurius was later built by White Fang, who had the Gundam Scientists install it with a mobile doll control system based on Heero’s recorded combat data. This second Mercurius was deployed alongside a second Vayeate to pursue Hilde Schbeiker, who had stolen important data from the battleship Libra. However, both mobile dolls were destroyed by Duo Maxwell’s Gundam Deathscythe Hell, demonstrating that whilst the mobile dolls could replicate pilot tactics, they lacked the adaptability of human pilots.

Appearances

The OZ-13MSX2 Mercurius appeared in the following works:

Mobile Suit Gundam Wing (anime series, episodes 20-45)
Mobile Suit Gundam Wing Endless Waltz: Glory of the Losers (manga)
Gundam Build Fighters (anime)
Gundam Build Fighters Try (anime)
SD Gundam G Generation Cross Rays (video game)

External links

OZ-13MSX2 Mercurius on the Gundam Wiki